Electrical signal device and system



Oct. 12, 1937. E. M. SQUIRE ET AL ELECTRICAL SIGNAL DEVICE AND SYSTEM ifzatzzfor-ss [2 77221 a fibuz're 0/1 22 K 726d Filed June 20, 1935 Patented Oct. 1 2, i937 ELECTRICAL SIGNAL DEVICE AND SYSTEM Edmund M. Squire, Brooklyn, N. Y., and Owen W. Kennedy, Boylston, Mass, assignors to Signal Engineering & Manufacturing Company, NewYork, N. Y., a corporation of Massachusetts Application June 20, 1935, Serial No. 27,576

6 Claims.

The present invention relates to'electrically operated signals, and has for its object to provide an improved signal device and a system partiou larly adapted for use in connection with exist- 6' ing telephone installations for the purpose of signaling incoming calls in a manner different from that of the telephone bells usually employed.

In the copending application of John H. Wheelock, Serial No. 697,417 filed November 10, 1933, there is shown and described an auxiliary signaling device of the above indicated character, with each signal obtaining its operating current from a source independent of the telephone installation, such as any light or power circuit, while receiving its primary energization from telephone ringing current. Furthermore, each auxiliary signal unit is so connected to the bell of the existing telephone installation that while the auxiliary signal will ordinarily be operated in place of the telephone bell, the latter will be automatically rendered operative upon any failure of the source from which the auxiliary signal is energized, or upon disconnection of the unit from this source.

25 While an auxiliary signal such as is described in the aforementioned Wheelock application is entirely satisfactory for the general purpose of signaling an incoming telephone call in place of the usual bell, no provision is made for causing the telephone bell to ring in the event of the occurrence of conditions which would render the auxiliary signal inoperative. Accordingly, the present invention provides means whereby an auxiliary signal of the type disclosed in the Wheelock application is continuously supervised, so that the telephone bell is automatically placed in condition for ringing in response to an incoming call upon the occurrence of any abnormal condition which would prevent the auxiliary signal from functioning. The above and other advantageous features of the invention are hereinafter more fully set forth in the following description with reference to the accompanying drawing, in which:

45 Fig. 1 is a general wiring diagram illustrating the manner of installing auxiliary signals embodying the invention in connection with telephone subscribers stations.

Fig. 2 is a view showing, on an enlarged scale, the construction of one of the auxiliary signal units.

Fig. 3 is a view similar to Fig. 2,'illustrating a modification of the invention.

Like reference characters refer to like parts in 55 the different figures.

Referring first to Fig. 1, there is illustrated diagrammatically, a number of subscribers stations S, each providing the usual telephone instrument as indicated, and. a subscribers equipment box B, including a bell, all of usual construction. The complete wiring of the telephone set of a subscribers station S is simplified to the extent of showing only conductors 1) leading to each box B from the central exchange C, with ringing means indicated at K associated with the conductors I), see Fig. 2. As is usual, the conductors b are adapted to be energized at the central station C, so that telephone ringing current is transmitted to any box of a subscribers station S upon operation of the ringing means K at the central station.

Associated with each subscribers station S is a portable signal unit I, preferably of the single stroke chime type described in the aforementioned Wheelock application. Each signal unit l provides a cable 2 carrying at its end a suitable plug 3 for insertion in a power outlet 4 located adjacent to the subscribers station S. Each outlet 4 is energized from the mains 5 of a wiring installation, such as is usually provided for furnishing light and power to the building in which the subscribers telephone set S is located. A signal unit I also provides a flexible conductor cord 6 having a number of tips I for convenient connection to a terminal block 8 on the subscribers instrument box B, so that to install a signal unit it is only necessary to mount the unit adjacent to the nearest box B and power outlet 4, followed by insertion of the plug 3 in an outlet 4 and'connection of the cord 6 to the box terminal block 8.

Referring now to Fig. 2, each signal unit I consists of a resonant chime member 9 disposed in the path of movement of a magnetic plunger 10 movable axially within an operating winding ll. With the winding II in a deenergized condition, only the upper end of the plunger ID is disposed within the solenoid, so that energization of the winding II is adapted to draw the plunger upwardly to strike the resonant member 9 a single sharp blow. One terminal of the winding H is connected directly to one of the conductors 2a of the cable 2, while the other winding terminal II is connected in series with a winding I2 of a supervisory relay through a condenser l3. The current flowing through the winding II in series with the winding [2 is not sufficient to pull up the plunger I0, although sufficient current traverses winding l2 to maintain the bridging member l4 carried by its armature 12a in engagement with spaced stationary contacts I5 and. IS. The contact I5 is connected to one terminal of an auxiliary winding ll forming part of the signal unit, with the other terminal of winding l7 connected through a condenser 18 to one conductor 6a of the cord 5 leading to the box B. The other contact I6 of the supervisory relay is connected V to a second conductor fib'leading to the box B,

so that when the space between the contacts l5 and I6 is closed by the bridging member I4, the

terminals of the auxiliary winding I! are connected across the line terminals L-l and L2 of the box B in circuit with the condenser l8.

The armature Ila underthecontrolof-winding l'l carries separate contactarms l9 and 20 insulated from each other, whicharms'are adapt 7 ed to engage stationary contacts 2| and 22 retact 2! is connected to the signal winding II in parallel with one side of the condenser l3. The

7 other contact arm Zilfis connected to the power conductor 2a, while its cooperating contact 22 is connected in parallel with the supervisory winding l2 and the opposite side of the condenser H3.

The equipment in the box B is of any usual type, and is shown .as providing bell ringing coils '23, which upon energization by ringing current will cause the-subscribers bell to ring. One terminal of the ringer coils 23 is connected to box line terminal L2, which in turn is connected to one conductor 1) leading from the ringing means K, while the other ringer coil terminal is connected to the third conductor 60 of the cord 6. This conductor to is connected to one of a pair of spaced stationary contacts 24, the other of which is connected to the conductor 6b in parallel with the contact l6. Ifhe gap between the spaced contacts 26 is adapted to be closed by the bridging member i only upon deenergization of the supervisory winding l2. Consequently, the conductor 6b, which is connected permanently through box line terminal LI to the other conductor b from the ringing means K is adapted to transmit ringing current either to the amiliary signal winding I! or to the ringer coils 23, entirely depending upon the position of the bridging member Hi with reference to the cooperating pairs of spaced contacts l5, l6 and 24, 24. .7

With the: plug 3 of the signal unit I inserted in a power outlet 4, it is obvious that; the terminal of the ringer coils 23 connected to the contact 24 by conductor 6c will be maintained disconnected from the returnconductor 62) so long as supervisory current flowing through the winding VIZ maintains the bridging member l4 out of engagement with the spaced contacts 24. i Therefore, when the ringing means K is operated to supply jringing current to this particular subscribers station S, the bell will not berung, but

the ringing current will energize-the auxiliary signal winding I! to cause its contact arms l9 and 20 to engage stationary contacts 2| and 22.

Energization of the auxiliary winding [1 has the effect of changing theseries connection of the windings H, and I2 across the supply mains to a parallel circuit relation, due to the fact that closure of contacts l9 and 2! connects one terminal of winding II to the conductor 2b, while closure of contacts 26 and 22 connects the corresponding terminal of winding l2 to conductor 2a. Upon connection of the winding H directly across the supply mains, its full 'energization.

draws the plunger I upwardly to strike the resoe nant member 9 a single sharp blow, the plunger remaining in this position as long as ringing current is applied. The sound emitted by the resonant member 9- is of a clear penetrating quality, and a single stroke thereon is sufficient to call the subscrib-ers attention to the fact that there is an incoming call. In case the subscriber does not answer immediately, subsequent re-applications of ringing current, as is the usual practice, results in reenergizations of the winding H to again sound the chime one or more strokes. Obviously, recurrent strokes of the chime will be much less disturbing to the ear than the continued ringing of the bell in box B during the full period of application of ringing current from the central station C. The connection of the supervisory winding l2 directly across the supply mains, upon closure ofcontacts 2E! and 22, insures the continued energization of this winding, so that the bell is maintained inoperative as before.

Upon failure of the source supplying the conductors 2a and 21), upon disconnection of the signal unit from the outlet 4, or upon a break in the circuit of the signal operating winding H, the deenergization of winding [2 will result in two things:first, dropping back of the bridging member M to engage the spaced contacts 2 will establish the circuit of the ringer coils 23 from the conductor Eicto the conductor fib,second, disengagement of the bridging member Hi from the contacts and it will entirely disconnect the auxiliary winding I? from the conductor 61). Therefore, when ringing current is applied with the winding l2 deenergized, as a result of any one of the three occurrences mentioned above,

only the ringer coils 23 will be energized to sound the bell at the subscribers station. In other words, upon the occurrence or any abnormal condition which renders the auxiliary signal inoperative, the bell will be rung in response to an incoming call, thereby insuring continuity of telephone service. I On the other hand, so long as the supervisory winding l2 remains energized, the chime signal will be sounded in response to each application of ringing current. While the supply mains 5 are indicated as being energized from an alternating current source, the auxiliary signal will operate just as effectively when utilizing a direct current source by substituting a resistor 25 for the condenser i3 in the circuit between the windings El and I2, as indicated in dotted lines in-Fig. 2.

Referring now to Fig. 3, there is shown a modification of the manner of supervising the winding H, wherein a resistor 26 is connected between one terminal of the winding H and the conductor 219. With the resistor 26 in circuit with the winding l I, its current is reduced to such an extent that the plunger iii is held slightly above its lowermost position, as indicated in full lines. However, should there occur a break in the winding 5 l, the plunger Iii will drop to its lowermost position indicated in dotted lines.

The same terminal of the winding II' which is connected to the resistor 26 is also connected to one of a pair of spaced stationary contacts 21', the other contact of this pair being connected to power conductor 2b. The contacts 21 are adapted to be connected by a bridging member 28 under the control of a winding l1, one terminal of which is connected through condenser l8 to the conductor 611 leading from the line terminal L2 of the subscribers station. The other terminal of winding I1 is connected to a stationary contact 29 normally in engagement with a flexible contact 30 connected to conductor 61) leading from box terminal Ll.

With the plunger 10 held in its slightly raised positon by the supervisory current traversing winding ll, an insulated tip 30a of the contact 30 is just out of engagement with the lower end of plunger It. Consequently, an application of ringing current to the subscribers station will cause energization of winding I1, and the closure of the gap between contacts 21 to short circuit the resistor 26 and fully energize the signal winding H. In other words, the main signal winding II will function in exactly the same manner as the winding l I of Fig. 2, as long as it is traversed by the supervisory current.

Upon the occurrence of a break in the circuit of the winding II, the plunger ID will fall to its lowermost position, thereby moving contact 30 out of engagement with contact 29 and causing it to engage a lower contact 3|. Since contact 3| is connected to conductor to leading to the bell coils 23, the telephone bell. will be sounded upon each application of ringing current so long as the plungerlli remains in its lowermost position,

as a result of the absence of supervisory current flowing in the winding II.

From the foregoing, it is apparent that by the present invention there is provided an improved signal unit that is particularly adapted for use in connection with existing telephone installations for the purpose of indicating incoming calls at any subscribers station in a more pleasing and effective manner than that afforded by the usual telephone bell. At the same time, the occurrence of any abnormal condition which renders the auxiliary signal inoperative immediately results in the indication of an incoming call being restored to the telephone ringer.

We claim:

1. In an electrical signal system, the combination with separate current sources, a signal device comprising a winding which causes operation of said signal when fully energized from one current source, a second winding responsive to the other current source for controlling the connection of the signal operating winding to the first source, a second signal device and means responsive to the flow of supervisory current of low value through said signal operating winding from said first-named source for maintaining a circuit to said second winding and for also maintaining the second signal device inoperative from said other current source.

2. In an electrical signal system, the combination with separate current sources, a signal device comprising a winding which causes operation of said signal when fully energized from one current source, a second winding responsive to the other current source for controlling the connection of the signal operating winding to the first source, a second signal device and means responsive to the flow of supervisory current of low value through said signal operating winding from said first-named source for maintaining a circuit to said second Winding and for also maintaining the second signal device inoperative from said other current source, with the occurrence of any interruption of the flow of supervisory current through said operating winding of the first signal device serving to automatically restore the second-named signal device to an operative condition.

3. In a telephone system, the combination with a source of ringing current, a telephone ringer at a subscribers station and a source of commercial power, of an auxiliary signal device comprising a winding which causes operation of said signal when fully energized from said power source, a second winding responsive to a ringing current for controlling the connection of said signal operating winding to said power source, and means responsive to the flow of supervisory current of low value through said signal operating winding from said power source for maintaining a circuit to said second winding and for maintaining said ringer inoperative by ringing current.

4. In a telephone system, the combination with a source of ringing current, a telephone ringer at a subscribers station and a source of commercial power, of an auxiliary signal device comprising a Winding which causes operation of said signal when fully energized from said power source, a second winding responsive to a ringing current for controlling the connection of said signal operating winding to said power source, and means responsive to the flow of supervisory current of low value through said signal operating winding from said power source for maintaining a circuit to said second winding and for maintaining said ringer inoperative by ringing current, with the occurrence of any interruption of the flow of supervisory current in said operating winding serving to restore said ringer to an operative condition.

5. A signal unit of the class described, comprising an operating winding responsive to one current source, a second winding responsive to another current source for controlling the connection of the operating winding to the first source, and means responsive to the flow of supervisory current through said operating winding from said first-named source for maintaining a circuit to said second winding.

6. A signal unit of the class described, comprising an operating winding responsive to one current source, a second winding responsive to another current source for controlling the connection of the operating winding to the first source, and a third winding normally in series with the operating winding for maintaining a circuit to said second winding, as long as supervisory current flows through the first and third windings.

EDMUND M. SQUIRE. OWEN W. KENNEDY. 

